Unthrottled internal combustion engine



Jan. 19, 1965 l. H. HALLBx-:RG

UNTHROTTLED INTERNAL COMBUSTION ENGINE Original Filed Sept. 28. 1960United States Patent O Y UNH-momen ThisV application is a divisionrofapplication Serial No.`

3,166,051 Patented Jan. 19, 1965"' Pce.

an engine, according to my invention, complete scaveng-V ingA isvnot'interfered with becauseafter combustion the auxiliary ignitionchamber and the res'dual'co'rnbustion space become one chamber. A A

It is therefore a primary object `of kmy invention. to

" provide an internal combustion engine which liaschar-Y 59,087, filedSeptember 28, 1960 for Unthrottled Internal Y Combustion Engine, nowPatent No. 3,079,901. j

My invention relatesrto unthrottled internal combus` tion engines, and,more particularly,rto -an engine of this type wherein' the fuel isignited by means of a spark'- plug and wherein an auxiliary ignitionchamber is provided by `means including an irregular 'crown of thepiston when the piston com es into close proximitywithtzo a'pocket 'orignition ,cell anda main combustion chamber are Vprovided each having aseparate fuel, supply means-, e. @lt is another object of. myinve'ntionYtoreduce the the cylinder head at the top of the piston stroke.

A full complement of air is provided with each cycle of operation, and,only the amount of fuel supplied to the engine varies, thereforeimproving 'thermal etilciencyvwhichresults in improved fuel economy anda reduction of hydrocarbon content in .the exhaust gas as compared withmost conventional spark ignition en gines which power is changed byvaryingboth fuel and air quantity to maintain a fixed mixture ratio. e Y

Most unthrottled internal combustion, engines Yare complex, requiringconsiderable engine design change,V leading to highcosts and thereforegiving little cornmercial promise. The engine, according to myinvention, uses conventional parts with slightV modification in theshape of the crown of the piston and possibly the cylinder head and onlythe addition of a sirnplied injection system. Engines of this type havebeen built wherein an auxiliary ignition chamber is provided in thecylinder head. Such an ignition chamber has a constricted throatconnected with a main combustion chamber which lies between the pistonhead and the cylinder head. A spark plug is inserted in the auxiliaryignition chamber and fuel is injected into the auxiliary'ignitionchamber whereby a rich mixture is provided in the aux-V iliary ignitionchamber and a lean mixture in the main combustion chamber. VThisarrangement provides a mixture suiliciently Vrich for ignition by spark.However, the constriction between the auxiliary ignition chamber and themain combustion chamber may become exceedingly hot, thereby causingpre-ignition. In an engine, according to my invention, a combustionspace Vis provided at top dead center of the piston between the lcrownof the piston'and the cylinder head which comprises a'u j a It is alsoan important Vobject of acteristics which improve thermal eiciencyresulting in improved fuel economy at part load and reduction of.hydrocarbons in the exhaust gas.

It is also a primary 'object of my invention to provide a spark ignitionunthrottled internal combustion engine having an auxiliary ignitionchamber and a residual cornbustion space wherein complete scavangingoccurs with' respect to the `auxiliary ignition chamber. J

g It is an important object of my invention to provide` an unthrottledinternalcornbustion engine which has the smooth combustioncharacteristicsof a conventional internal combustion engine.

my invention to provide an unthrottledrinternal combustion enginewherein possibilitiesrof preignition in unthrottled internal combustionengines.v f

` It-isafurther objectrof'my invention to provide an unthrottled sparkignition internal combustion engine which is simple 'in construction,requiring little change in engine .design as compared with throttledinternal combustion engines and thereforeuis low in lmanufactur-i ingcosts.. l,

It is still another "object of my invention to provide an unthrottledinternal combustion engine wherein the pressure rise of the ignited fuelis gradual thereby giving the smoother combustion characteristics of anOtto cycle engine rather than-the rough Vcharacteristics -of a dieselengine. l j

My invention consists of the novel constructions, arrangements anddevices'to be hereinafter described and claimed'for carrying outitheabove `stated objects and such other objects aswill be apparent from thefollowing description of the invention, illustrated with reference tothe accompanying drawings, wherein: Y

ln the drawing a piston SS-,provided'with a ridge 87 on an irregularVcrownvlltlg is operable in a cylinder-91. The ridge 87 provides apocket 36 which forms an auxil- Y iary ignition chamber, whenv thepiston 88 is at approximately *top dead center aud on the opposite sideof the auxiliary ignition chamber and a residual combustion space whichis comparable to the ymain combustion 1 chambers of currently knownthrottled internal combustion engines. However, the design of vmy engineisv such that when the fuel is ignited in the auxiliary ignitionchamber, which is of a richer mixture than that of itionifrom such acauseiseliminated. Complete scavanging of the auxiliary ignitionchamber, 'after combustion, v isnot possible in the type of enginereferred to above because of the constriction between the auxiliarycombustion chamber and the main combustion chamber.

This incomplete scavenging results in a limitation ofthe" maximum powerobtainable from a given size enginel and dilution of the ignitionmixture witheexhaustrgases. In

ridge 87' a mai-n combustion chamber 90 is formed. AA variable quantityinjection nozzle `84 and a'constan-t vcjuanl tity injection nozzle 85are'provided for supplying fuel to the main combustion chamber-90 andthe pocketv 86, respectively.y A spark plug 1S is inserted in the areaof thepocket 86.

FIG. lis a sidejelevational view, partially in section, ofthe piston,cylinder, injection nozzles and spark plug ofanunthrottled internalcombustion engine, and j FIG. 2 is a plan view of the'crown of thev'piston dis'- closedinFIG. l. e e

fln operation, thevariable quantity injection nozzle 84 injects a leanvariable quantity of1 fuel lat some point during the intake stroke or atthe.V beginning of the com-v pressionv stroke. Fuel for this Vpurposecould also be provided by-a carburetor with a variable jet. Fuel fromVthe constant.` quantity injection-nozzle 8,5'is supplied in a smallconstant quantity into the pocket 86,.whicl1,V at T.D.C. of the pistonSS'bec'oniesan auxiliary .ignition fchamber which is formed within theconfines" of the 'ridge 8'] on the irregularv crown 10g ofthe piston3.8, and

.Y the ylinder head sa, when the piston ss `atun.c.V

'I'his fuel mixture provided sparkplug 18.V From this focal point ofignition, the

'combustion spreads to the maincombustion vchamber 970.

For the sake of simplicity and clarity, the invention has been describedasvapplied to an engine having butone -f cylinder; obviously itis-applicable toa multipleV cylinder internal combustion engine. A f f Yt It is to be understood that the` inventionis not to be limitedtorthespeciicV constructions` and arrangements` by the constantquantityv in,-Y jection nozzle 85 is suflciently rich to be ignited bythe v c Y A, I irregular crown and reciprocally operable in saidcylinder, a combustion space between said cylinder head and said Yirregular crown, the said combustion spac'ecomprising an auxiliaryignition chamber `and a residual combustion space when the said pistonis substantially at T.D.C., said irregular'crown comprising'a ridgewhich'separates said auxiliary ignition chamber from said residualcombustion space, a spark plug inserted in saidauxiliary ignitionlvchamber, fuel injection meansfor supplying fuel to said shown. anddescribed, exceptv only'insofar as the'cla'ims t may be so limited, asit willY be understood to those skilled in the .art that changes may bemadenwithout-departing from the principles of the invention. Y `Iclaimzr 1. In anrunthrottled internal combustion engine having l Y acylinder, air intake means and exhaust means forsai/d cylinder, acylinderhead, a piston, saidV piston having an j Y irregular crown andreciprocally operable insaid cylinder,` a combustion space between saidcylinder headV tand said irregularvcrowmithe said combustion spacecomprising an` Y auxiliary ignitionV chamber andV aY residual tcornbustionfV i space when'thersaid piston Yis)-"substantiallyat T.D.C.,`said Y irregular crown providing means which separates. saidj auxiliaryignition'chamberfrom ksaid residual combustion'V space, aspark-pluginserted in saidk auxiliary,ignitionV chamber, VVfuel injection meansforrsupplying fuel to-jsaid` auxiliary ignition chamber, fuel injectionmeansfor sup- ,Y 1

plying fuel to said "combustionespace,gsaidfuel'supply n being richerinmixture in said auxiliary ignition char'rrber'Y than in theAremainder-of .saidcombustion `space `and means forsupplying electriccurrent to 4said spark plug to thereby yignite said Vricher fuelmixturein said,auxiliary, t ignition chamber.'Y Y

k2. In an unthrottledV internal combustion engine `'a cylinder, airintake means'andexhaust meansfor said Y cylinder, a cylinder head, `apiston, piston having' an auxiliary ignition chamber, fuel injectionmeans for supplying fuel to said combustion space, said fuel supplybeing richer in mixture inY said auxiliary ignition chamber Y, than inthe remainder of said combustion space and means for supplying electriccurrent to said'spark plug to` thereby ignite said richer fuel mixturein saidauxiliary ignition chamber.

v f 3. In an unthrottled internalcombustion enginefliav-vj Y ing acylinder, airintake meansA andexhaust meansfor 'said'cylinden acylinderhead, a piston, saidpiston having van irregular crown andreciprocally operable said cylf inder, a combustion spacefbetween saidjcylinder head and said Yir'regularcrown, the Ysaid combustion'spacecomprising'an auxiliary ignition chamber `and a residual corn-'.bustion's'pa'ce whenfthe said piston is substantially at p '-T.D.C.,fsaid irregular crown comprising va ridge which separates saidauxiliary ignition'chamber from said resid- -ual Vcombustionl space, aVsparkV pluginserted'in,saidA rauxiliary ignition chamber, firstfuelfsupplyV meansV forV Y supplying fuel to said auxiliary ignitionchamber, second fuel supplyV meansV for supplyingY fuel to saidcombustion space, said fuel supplyY being richerljrinrmixture in saidauxiliary ignition *chamberrth'an'i'n the remainder of saidY combustionspace and means fforsupplying .electric 'current lto said sparkplug tothereby ignite said Aricher fuel.A

mixture in said auxiliary ignition chamber,

v Noreferences cited.`

1. IN AN UNTHROTTLED INTERNAL COMBUSTION ENGINE HAVING A CYLINDER, AIRINTAKE MEANS AND EXHAUST MEANS FOR SAID CYLINDER, A CYLINDER HEAD, APISTON, SAID PISTON HAVING AN IRREGULAR CROWN AND RECIPROCALLY OPERABLEIN SAID CYLINDER A COMBUSTION SPACE BETWEEN SAID CYLINDER HEAD AND SAIDIRREGULAR CROWN, THE SAID COMBUSTION SPACE COMPRISING AN AUXILIARYIGNITION CHAMBER AND A RESIDUAL COMBUSTION SPACE WITH THE SAID PISTON ISSUBSTNTIALLY AT T.D.C., SAID IRREGULAR CROWN PROVIDING MEANS WHICHSEPARATES SAID AUXILIARY IGNITION CHAMBER FROM SAID RESIDUAL COMBUSTIONSPACE, A SPARK INSERTED IN SAID AUXILIARY IGNITION CHAMBER, FUELINJECTION MEANS FOR SUPPLY FUEL TO SAID AUXILIARY IGNITION CHAMBER, FUELINJECTION MEANS FOR SUPPLYING FUEL TO SAID COMBUSTION SPACE, SAID FUELSUPPLY BEING RICHER IN MIXTURE IN SAID AUXILIARY IGNITION CHAMBER THANIN THE REMAINDER OF SAID COMBUSTION SPACE AND MEANS FOR SUPPLYINGELECTRIC CURRENT TO SAID SPARK PLUG TO THEREBY IGNITE SAID RICHER FUELMIXTURE IN SAID AUXILIARY IGNITION CHAMBER.